Sofa having a curved backrest



FIG. 1 is a perspective view of a sofa having a curved backrest depicting a preferred embodiment of the new design;

FIG. 2 is a front elevation view of the sofa;

FIG. 3 is a top plan view of the sofa; and,

FIG. 4 is a side elevation view of the sofa, the other side being a mirror image thereof. 

The ornamental design for a sofa having a curved backrest, as shown and described. 